In the operation of a Tungsten Inert Gas (TIG) welder some means must be provided to initiate the arc. In some TIG welders a high power surge is provided in order to initiate ionization of the gas between the workpiece and the welder electrode. Once the arc is initiated, the power is reduced to a fixed level that will maintain the arc.
In TIG welding the distance between the workpiece and electrode is very critical to assure arc-stability. If the gap becomes too large, the arc will be extinguished. If the gap becomes too small, the arc will becomes too hot and electrode damage will result. In order to maintain the desired arc gap width for critical welding, fixtures are used to position the electrode relative to the workpiece. Fixtures can be costly and time consuming to make, particularly where only a few similar pieces are to be welded.
In other methods of TIG welding an R.F. arc is established to provide an ionized path for the welding arc. This technique requires that an R.F. supply be incorporated in the TIG welder increasing its cost. The use of an R.F. arc also requires that R.F. shielding be provided to prevent radio interference.
It is therefore an object of this invention to provide an improved means of establishing and maintaining an arc in a TIG welder.
Another object of this invention is to provide a TIG welder electrode structure which does not require an R.F. supply or other special power supply to initiate and maintain the welding arc.